Isolate feature work with git worktrees

Create and verify isolated git worktrees for parallel branch work

When feature work requires complete isolation from current workspace without branch switching.

• · .gitignore file
• · project root
• · branch name

• · initialized worktree at path
• · passing test baseline

• · git
• · bash

Repository initialized; package.json/Cargo.toml/equivalent present

• · directory not ignored
• · baseline tests fail
• · setup tool not found

• · Explicit .gitignore verification
• · baseline test pass confirmation
• · supported by Jesse's rule